[chore] clarify reason for deprecation of event.name (#2983)

Author: thompson-tomo

docs/registry/attributes/event.md

@@ -9,4 +9,4 @@ Attributes for Events represented using Log Records.
 
 | Attribute | Type | Description | Examples | Stability |
 |---|---|---|---|---|
-| <a id="event-name" href="#event-name">`event.name`</a> | string | Identifies the class / type of event. | `browser.mouse.click`; `device.app.lifecycle` | ![Deprecated](https://img.shields.io/badge/-deprecated-red)<br>Replaced by EventName top-level field on the LogRecord. |
+| <a id="event-name" href="#event-name">`event.name`</a> | string | Identifies the class / type of event. | `browser.mouse.click`; `device.app.lifecycle` | ![Deprecated](https://img.shields.io/badge/-deprecated-red)<br>The value of this attribute MUST now be set as the value of the EventName field on the LogRecord to indicate that the LogRecord represents an Event. |

model/event/deprecated/registry-deprecated.yaml

@@ -11,7 +11,7 @@ groups:
         deprecated:
           reason: uncategorized
           note: >
-            Replaced by EventName top-level field on the LogRecord.
+            The value of this attribute MUST now be set as the value of the EventName field on the LogRecord to indicate that the LogRecord represents an Event.
         brief: >
           Identifies the class / type of event.
         examples: ["browser.mouse.click", "device.app.lifecycle"]